Determination of lead in plasma and studies on its relationship to lead in erythrocytes.

Plasma lead concentrations were determined in 103 subjects, including lead workers and those not occupationally exposed to lead. The plasma lead concentrations in each blood lead group were about half those previously reported, and this difference was shown to be due to the use of heparin instead of ethylenediaminetetra-acetic acid (EDTA) as the anticoagulant. The method for the determination of lead in plasma is detailed and its accuracy discussed. The plasma lead concentration was found to increase with the erythrocyte lead concentration, the mean equilibrium ratio between the two being about 0.74%. The effect of a sudden disturbance of the equilibrium condition on this ratio was investigated. This work supports the view that whole blood lead concentrations should be corrected for haematocrit.